The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
The functional vessels of human and animal bodies, such as blood vessels and ducts, occasionally weaken or even rupture. For example, the aortic wall can weaken, resulting in an aneurysm. Upon further exposure to hemodynamic forces, such an aneurysm can rupture, resulting in an aortic dissection.
One treatment option for weakened, aneurysmal, or ruptured vessels is the use of stent grafts, placed either surgically or endovascularly. A stent graft may be, for example, a tubular structure that is placed into a body lumen, such as the aorta, to, for example, span a weakened area or to maintain patency of the body lumen. When treating aortic aneurysms or dissections, a stent graft is generally placed within the damaged portion of the aorta to bypass the weakened area of the aorta or to seal a tear (dissection) in the aorta, thereby reestablishing a closed pathway for blood to flow through.
While aortic aneurysms and dissections can occur along the length of the aorta, they are particularly difficult to treat when occurring in the ascending aorta near the sinotubular junction. Conventional seal stents often do not provide an adequate seal near the sinotubular junction because of its unusual anatomy. While the ascending aorta is substantially cylindrical in shape, the sinotubular junction marks a transition point from this cylindrical anatomy to the annular shape of the aortic root. Thus, the transition point of the sinotubular junction sees an anatomical change in both size and diameter. Due to these anatomical changes, stent grafts positioned near the sinotubular junction have issues with leakage and sufficient sealing of the aorta. Thus, it is desirable to provide a stent graft that can provide an adequate seal in the ascending aorta near the sinotubular junction.